git.lttng.org Git - lttng-ust.git/blob

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2015 EfficiOS Inc.
   5  * Copyright (C) 2015 Alexandre Montplaisir <alexmonthy@efficios.com>
   6  */
   7
   8 package org.lttng.ust.agent.client;
   9
  10 import java.util.Collection;
  11
  12 import org.lttng.ust.agent.session.EventRule;
  13
  14 /**
  15  * TCP client listener interface.
  16  *
  17  * This interface contains callbacks that are called when the TCP client
  18  * receives commands from the session daemon. These callbacks will define what
  19  * do to with each command.
  20  *
  21  * @author Alexandre Montplaisir
  22  */
  23 public interface ILttngTcpClientListener {
  24
  25         /**
  26          * Callback for the TCP client to notify the listener agent that a request
  27          * for enabling an event rule was sent from the session daemon.
  28          *
  29          * @param eventRule
  30          *            The event rule that was requested to be enabled
  31          * @return Since we do not track individual sessions, right now this command
  32          *         cannot fail. It will always return true.
  33          */
  34         boolean eventEnabled(EventRule eventRule);
  35
  36         /**
  37          * Callback for the TCP client to notify the listener agent that a request
  38          * for disabling an event was sent from the session daemon.
  39          *
  40          * @param eventName
  41          *            The name of the event that was requested to be disabled.
  42          * @return True if the command completed successfully, false if we should
  43          *         report an error (event was not enabled, etc.)
  44          */
  45         boolean eventDisabled(String eventName);
  46
  47         /**
  48          * Callback for the TCP client to notify the listener agent that a request
  49          * for enabling an application-specific context was sent from the session
  50          * daemon.
  51          *
  52          * @param contextRetrieverName
  53          *            The name of the retriever in which the context is present.
  54          *            This is used to namespace the contexts.
  55          * @param contextName
  56          *            The name of the context that was requested to be enabled
  57          * @return Since we do not track individual sessions, right now this command
  58          *         cannot fail. It will always return true.
  59          */
  60         boolean appContextEnabled(String contextRetrieverName, String contextName);
  61
  62         /**
  63          * Callback for the TCP client to notify the listener agent that a request
  64          * for disabling an application-specific context was sent from the session
  65          * daemon.
  66          *
  67          * @param contextRetrieverName
  68          *            The name of the retriever in which the context is present.
  69          *            This is used to namespace the contexts.
  70          * @param contextName
  71          *            The name of the context that was requested to be disabled.
  72          * @return True if the command completed successfully, false if we should
  73          *         report an error (context was not previously enabled for example)
  74          */
  75         boolean appContextDisabled(String contextRetrieverName, String contextName);
  76
  77         /**
  78          * List the events that are available in the agent's tracing domain.
  79          *
  80          * In Java terms, this means loggers that have at least one LTTng log
  81          * handler of their corresponding domain attached.
  82          *
  83          * @return The list of available events
  84          */
  85         Collection<String> listAvailableEvents();
  86 }